Re: 答复: excessive number of db writer

  • From: amonte <ax.mount@xxxxxxxxx>
  • To: "Serol_Luo (BJ)" <Serol_Luo@xxxxxxxxx>
  • Date: Wed, 6 Sep 2006 11:44:57 +0200

Hi

It is not from a production system (YET), they told me to put this in
production when I upgrade this to 9i in 2 weeks time. So I dont have
Statspack whatsoever. They say is to prevent performance problems, i.e being
proactive than reactive :-O



On 9/6/06, Serol_Luo (BJ) <Serol_Luo@xxxxxxxxx> wrote: 

 Maybe 2-statspack reports can help to measure if the change of DB-Writers
has any effect on database performance.

1 before change, 1 after change



==============================

Regards.

Serol Luo

SMIC / BJ-IT / SDBS

(010-)6785-5000 Ext:21012



-----原始邮件-----
*发件人:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx
]*代表 *K Gopalakrishnan
*发送时间:* 2006年9月6日 17:05
*收件人:* ax.mount@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
*主题:* Re: excessive number of db writer



Alex,

Did you get  an explanation for those suggestions?  It would be difficult
for us to comment on those changes without any additional details..

However, However,However, 20 DBWriters are certainly high for your
configuration ;)



Have a nice day !!
------------------------------------------------------------
Best Regards,
K Gopalakrishnan,
Co-Author: Oracle Wait Interface: Oracle Press 2004.
http://www.amazon.com/gp/product/007222729X/

Coming Soon: Oracle RAC Handbook, Oracle Press 2006
http://www.amazon.com/gp/product/007146509X/



----- Original Message ----
From: amonte <ax.mount@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx
Sent: Wednesday, September 6, 2006 1:39:51 AM
Subject: excessive number of db writer

Hi

I have been suggested by some Oracle Consultant to set 20 Database Writer
in a 12 CPU HP-UX Server.

Does anyone know what are the side effects of having excessive DBWR? I
detected a higher CPU usage (between, 1% to 2%) not sure if its due to the
number of Database Writer. Because when I increased the number of DBWR at
init.ora I also changed these parameters

_row_cache_cursors = 60
_kgl_latch_count = 59
_kghdsidx_count = 4
statistics_level = basic

again suugested by this guy.

TIA

Alex



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